title: Antimicrobial action of minocycline microspheres versus 810-nm diode laser on human dental plaque microcosm biofilms.
abstract: BACKGROUND
  The purpose of this study is to investigate the antimicrobial effects of minocycline hydrochloride microspheres versus infrared light at 810 nm from a diode laser on multispecies oral biofilms in vitro. These biofilms were grown from dental plaque inoculum (oral microcosms) and were obtained from six systemically healthy individuals with generalized chronic periodontitis.
  
  
  METHODS
  Multispecies biofilms were derived using supra- and subgingival plaque samples from mesio-buccal aspects of premolars and molars exhibiting probing depths in the 4- to 5-mm range and 1- to 2-mm attachment loss. Biofilms were developed anaerobically on blood agar surfaces in 96-well plates using a growth medium of prereduced, anaerobically sterilized brain-heart infusion with 2% horse serum. Minocycline HCl 1 mg microspheres were applied on biofilms on days 2 and 5 of their development. Biofilms were also exposed on days 2 and 5 of their growth to 810-nm light for 30 seconds using a power of 0.8 W in a continuous-wave mode. The susceptibility of microorganisms to minocycline or infrared light was evaluated by a colony-forming assay and DNA probe analysis at different time points.
  
  
  RESULTS
  At all time points of survival assessment, minocycline was more effective (>2 log10 colony-forming unit reduction) than light treatment (P <0.002). Microbial analysis did not reveal susceptibility of certain dental plaque pathogens to light, and it was not possible after treatment with minocycline due to lack of bacterial growth.
  
  
  CONCLUSIONS
  The cumulative action of minocycline microspheres on multispecies oral biofilms in vitro led to enhanced killing of microorganisms, whereas a single exposure of light at 810 nm exhibited minimal and non-selective antimicrobial effects.
authors.affiliation: Applied Molecular Photomedicine Laboratory, Department of Applied Oral Sciences, The Forsyth Institute, Cambridge, MA.
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Song
authors.forename: Tina
authors.initials: T
authors.lastname: Yaskell
authors.forename: Vanja
authors.initials: V
authors.lastname: Klepac-Ceraj
authors.forename: Michael C
authors.initials: MC
authors.lastname: Lynch
authors.forename: Nikolaos S
authors.initials: NS
authors.lastname: Soukos
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D058491:Bacterial Load / Q000187:drug effects / Q000528:radiation effects; D001431:Bacteriological Techniques; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development / Q000528:radiation effects; D055113:Chronic Periodontitis / Q000382:microbiology; D003773:Dental Plaque / Q000382:microbiology*; D005260:Female; D006801:Humans; D019344:Lactic Acid / Q000737:chemistry; D054023:Lasers, Semiconductor / Q000627:therapeutic use*; D028022:Low-Level Light Therapy / Q000379:methods; D008297:Male; D008863:Microspheres; D008875:Middle Aged; D008911:Minocycline / Q000008:administration & dosage / Q000627:therapeutic use*; D017622:Periodontal Attachment Loss / Q000382:microbiology; D010514:Periodontal Pocket / Q000382:microbiology; D011100:Polyglycolic Acid / Q000737:chemistry; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer
chemical_list: D000900:Anti-Bacterial Agents; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D008911:Minocycline